mirror of https://github.com/nuxt/nuxt.git
102 lines
2.8 KiB
JavaScript
102 lines
2.8 KiB
JavaScript
<%= isTest ? '// @vue/component' : '' %>
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import Vue from 'vue'
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const requestIdleCallback = window.requestIdleCallback ||
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function (cb) {
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const start = Date.now()
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return setTimeout(function () {
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cb({
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didTimeout: false,
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timeRemaining: function () {
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return Math.max(0, 50 - (Date.now() - start))
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},
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})
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}, 1)
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}
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const observer = window.IntersectionObserver && new window.IntersectionObserver(entries => {
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entries.forEach(({ intersectionRatio, target: link }) => {
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if (intersectionRatio <= 0) {
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return
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}
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link.__prefetch()
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})
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})
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export default {
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extends: Vue.component('RouterLink'),
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name: 'NuxtLink',
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props: {
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noPrefetch: {
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type: Boolean,
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default: false
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}<% if (router.linkPrefetchedClass) { %>,
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prefetchedClass: {
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type: String,
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default: '<%= router.linkPrefetchedClass %>'
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}<% } %>
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},
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mounted() {
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if (!this.noPrefetch) {
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requestIdleCallback(this.observe, { timeout: 2e3 })
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}
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},
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beforeDestroy() {
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if (this.__observed) {
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observer.unobserve(this.$el)
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delete this.$el.__prefetch
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}
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},
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methods: {
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observe() {
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// If no IntersectionObserver, avoid prefetching
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if (!observer) {
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return
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}
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// Add to observer
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if (this.shouldPrefetch()) {
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this.$el.__prefetch = this.prefetch.bind(this)
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observer.observe(this.$el)
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this.__observed = true
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}<% if (router.linkPrefetchedClass) { %> else {
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this.addPrefetchedClass()
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}<% } %>
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},
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shouldPrefetch() {
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return this.getPrefetchComponents().length > 0
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},
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canPrefetch() {
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const conn = navigator.connection
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const hasBadConnection = this.$nuxt.isOffline || (conn && ((conn.effectiveType || '').includes('2g') || conn.saveData))
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return !hasBadConnection
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},
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getPrefetchComponents() {
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const ref = this.$router.resolve(this.to, this.$route, this.append)
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const Components = ref.resolved.matched.map((r) => r.components.default)
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return Components.filter((Component) => typeof Component === 'function' && !Component.options && !Component.__prefetched)
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},
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prefetch() {
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if (!this.canPrefetch()) {
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return
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}
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// Stop obersing this link (in case of internet connection changes)
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observer.unobserve(this.$el)
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const Components = this.getPrefetchComponents()
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for (const Component of Components) {
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try {
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Component()
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Component.__prefetched = true
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} catch (e) {}
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}<% if (router.linkPrefetchedClass) { %>
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this.addPrefetchedClass()<% } %>
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}<% if (router.linkPrefetchedClass) { %>,
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addPrefetchedClass() {
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if (this.prefetchedClass !== 'false') {
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this.$el.className += (this.$el.className + ' ' + this.prefetchedClass).trim()
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}
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}<% } %>
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}
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}
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